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Brachial Plexus
Prof. Oluwadiya Kehindewww.oluwadiya.com
Introduction
• The brachial plexus is an arrangement of nerve fibres, running from the spine, formed by the ventral rami of the lower cervical and upper thoracic nerve roots, specifically from above the fifth cervical vertebra to underneath the first thoracic vertebra (C5-T1).
• It proceeds through the neck, the axilla (armpit region) and into the arm.
Levels (pneumonics)
Roots
Trunks
Divisions
Cords
Branches
Real
(Athletic) Trainers
Drink
Cold
Beer
Roots
• The ventral rami of spinal nerves C5 to T1 are referred to as the roots of the brachial plexus.
Trunks
• Shortly after emerging from the intervertebral foramina , the 5 roots unite to form three trunks.
• The ventral rami of C5 and C6 unite to form the Upper Trunk.
• The ventral ramus of C7 continues as the Middle Trunk.
• The ventral rami of C8 and T1 unite to form the Lower Trunk.
Divisions
• Each trunk splits into an anterior division and a posterior division.
• The anterior divisions usually supply flexor muscles
• The posterior divisions usually supply extensor muscles.
Cords• The anterior divisions of
the upper and middle trunks unite to form thelateral cord.
• The anterior division of the lower trunk continues as the medial cord.
• All 3 posterior divisions from each of the 3 cords all unite to form theposterior cord.
• The cords are named according to their position relative to the axillary artery.
RootsTrunkDivisionsCordsBranches
The Scheme of the Brachial Plexus
Branches of the brachial plexus
• Branches are either from portions of the brachial plexus (e.g. root, trunk, divisions and cords) or are terminal branches.
• Nerves that are branches from portions of the brachial plexus usually contain only one type of axon; either sensory or motor
• Terminal Branches are mixed nerves containing both sensory and motor axons.
Brachial Plexus and its branches
Netter’s Atlas 2nd ed
Branches from the root
Two nerves• Dorsal Scapular nerve
oDerived from C5 root o Innervates the
Rhomboid major and minor muscles
• Long Thoracic nerve oDerived from C 5,6,7 o Innervates the
serratus anterior muscle
Branches from the trunk
Two nerves• Both originates from the
Upper Trunk o Nerve to subclavius
muscle o Suprascapular nerve
o Innervates supra and infraspinatus muscles
Branches from the CordsFrom the Lateral Cord
• Lateral Pectoral nerve o Innervates the clavicular head of the pectoralis major
muscle From the Medial Cord
• Medial Pectoral nerve o Innervates the sternocostal head of the pectoralis
major muscle o Innervates the pectoralis minor muscle
• Cutaneous Branches oMedial brachial cutaneous
Carries sensation from the lower medial portion of the arm
oMedial antebrachial cutaneous Carries sensation from the medial (ulnar portion of
the forearm)
Note : The medial and lateral pectoral nerves often join together to act as a
single nerve innervating both the pectoralis major & minor muscles
Branches from the Cords
From the Posterior Cord• Lower Scapular nerve
o Supplies Teres Majoro Supplies Subscapularis
• Thoracodorsal nerveo Supplies Latissimus dorsi and Teres Major
• Upper Scapular nerveo Supplies Subscapularis
Terminal branches: Lateral cord
Musculocutaneous nerve is derived from the lateral cord. – This nerve innervates the muscles in the flexor
compartment of the arm – Carries sensation from the lateral ( radial) side of the
forearm. Lateral cord contributes also to the Median nerve
– Motor innervation to most of the flexors muscles in the forearm and intrinsic muscles of the thumb (thenar muscles).
– Sensory innervation is from the lateral ( radial) 31/2 digits (the thumb and first 21/2 fingers
Terminal branches: Medial Cord
Ulnar nerve is derived from the medial cord Motor innervation is mainly to intrinsic muscles of the hand Sensory innervation is from the medial ( ulnar) 1 & 1/2 digits
( the 5th. and 1/2 of the 4th. digits). Medial cord contributes also to the Median nerve
– Motor innervation is to most of the flexors muscles in the forearm and intrinsic muscles of the thumb (thenar muscles).
– Sensory innervation is from the lateral ( radial) 31/2 digits ( the thumb and first 2 and 1/2 fingers
Terminal branches: Posterior Cord
Axillary nerve is derived from the posterior cord. Motor innervation is deltoid and teres minor muscles that
act on the shoulder joint. Sensory innervation is from the skin just below the point of
the shoulder. Radial nerve is also derived from the posterior cord.
Called “Great Extensor Nerve” because it innervates the extensor muscles of the elbow, wrist and fingers.
Sensory innervation is from the skin on the dorsum of the hand on the radial side.
Branches Scheme
musculocutaneous n.
(C5-C7)
Netter’s Atlas of Human Anatomy 2nd ed
axillary n. (C5-C6)
radial n. (C5-T1)
Netter’s Atlas of Human Anatomy 2nd ed
Dorsal Scapular N.
Levator Scapulae
Rhomboid Major/Minor
Lateral Pectoral N.
Pectoralis Major/Minor
Suprascapular N. Infraspinatus
Supraspinatus
Musculocutaneous N.
Biceps Brachii
Brachialis
Coracobrachialis
Axillary N.
Deltoid
Teres Minor
Upper Subscapular N.
Subscapularis
Thoracodorsal N.
Latissimus Dorsi
Lower Subscapular N.
Subscapularis
Teres Major
Median Nerve.1. Abductor Pollicis
Brevis/Longus2. Flexor Carpi Radialis3. Flexor Digitorum
Superficialis4. Flexor Digitorum Profundus
(Lat. 2)5. Flexor Pollicis Brevis (Lat.) &
Longus6. Lumbricales (Lat. 2)7. Opponens Pollicis8. Palmaris Longus9. Pronator Quadratus10. Pronator Teres
Radial Nerve.1. Abductor Pollicis Brevis
2. Anconeus
3. Brachioradialis
4. Extensor Carpi Radialis Brevis/Longus
5. Extensor Carpi Ulnaris
6. Extensor Digiti Minimi
7. Extensor Digitorum Communis
8. Extensor Indicis
9. Extensor Pollicis Brevis/Longus
10. Supinator
11. Triceps Brachii
Ulnar N.1. Abductor Digiti Minimi2. Adductor Pollicis3. Dorsal Interossei4. Flexor Carpi Ulnaris5. Flexor Digiti Minimi6. Flexor Digitorum
Profundus(Med. 2)
7. Flexor Pollicis Brevis (Med.)
8. Lumbricals (Med. 2)9. Opponens Digiti Minimi10. Palmar Interossei
Long Thoracic N. Serratus Anterior
Medial Pectoral N. Pectoralis Major
upper limb -
cutaneous innervation
Netter’s Atlas of Human Anatomy 2nd ed
upper limb –
dermatome pattern
Netter’s Atlas of Human Anatomy 2nd ed
Any Question?
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